Delta Air Lines Inc. announced this week, that starting Jan. 1, 2015, it will reward passengers for the amount they spend on tickets, not the number of miles they fly. The change to Delta’s SkyMiles program will be great for people who buy expensive tickets in first-class, but bad for vacationers who shop for the cheapest fare.

Delta Air Lines Inc. said this week that starting Jan. 1, it will reward passengers for the amount they spend on tickets, not the number of miles they fly. The change to Delta’s SkyMiles program will be great for people who buy expensive tickets in first-class, but bad for vacationers who shop for the cheapest fare.

Delta’s decision has renewed the debate about whether airline frequent-flier programs are worthwhile for people who only fly a few times a year.

Non-elite members of SkyMiles will get five miles for every dollar they spend. Those are people who don’t travel enough to earn “status,” and many are extremely price-conscious. Meanwhile, elite frequent fliers will get up to 11 miles per dollar.

The changes will make SkyMiles more like loyalty programs at Southwest Airlines, JetBlue and Virgin America. The other behemoth loyalty programs — AAdvantage at American Airlines and MileagePlus at United Airlines — still base rewards on miles flown, for now.

Here’s how the Delta changes will work. Right now, all Delta members get 3,892 miles for a round trip between Los Angeles and Atlanta. But after Jan. 1:

— A non-elite member who buys a $486 economy fare (the price on delta.com for an upcoming flight on the route) will get 38 percent fewer miles, down to 2,430.

— The same traveler paying $1,726 (from delta.com for the same March flight) for a first-class seat will get 8,630 miles.

— A “Diamond Medallion” — the top elite level for SkyMiles — buying that first-class ticket will earn a whopping 18,986 miles, nearly eight times more than the vacationer back in seat 29B.

Delta won’t say exactly how many miles you’ll need for any given trip until late this year.

To see if you’ll earn less toward a free trip on Delta, head over to the calculator on the airline’s website: http://bit.ly/1hhwTBb.

Jere Jenkins did and was shocked.

“It cuts my miles. The best I can do is get half of what I’m getting now on most of those flights,” said the West Lafayette, Ind., man, who flies frequently on Delta for his job at a scientific-instruments company. The firm uses a travel agency that shops for low fares.

Delta has “treated me the best over the years,” Jenkins said, but that doesn’t mean he’ll remain loyal. He said that he’s also got elite status on American and US Airways, and “United is going to get a call.”

Brian Kelly, founder of ThePointsGuy.com, a website dedicated to travel-loyalty programs, said that if enough people like Jenkins switch, it’ll make United and American less likely to copy Delta’s approach.

Many travelers are reluctant to switch, especially once they’ve achieved elite status. Kelly suggested asking other airlines if they’ll match your status. Take a screen shot of your account, email it to the other airline and ask, “What can you do for me?”

Another approach, he said, is to credit miles flown on Delta to an account at partner Alaska Airlines, which still has a traditional miles program and lets you redeem trips on Air France, Emirates and other carriers.

When comparing programs, look at ease of redeeming awards, the number and quality of partner airlines on which you can fly, and availability of upgrades.

Some Delta customers have gone on Twitter and Facebook to complain about the SkyMiles changes. Paul Skrbec, a spokesman for the Atlanta-based airline, said it’s too early to gauge the response among its 92 million members — the airline is still contacting them.